Anesthesiology
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Randomized Controlled Trial Multicenter Study Clinical Trial
Cerebral blood flow and CO2 reactivity is similar during remifentanil/N2O and fentanyl/N2O anesthesia.
Remifentanil, a rapidly metabolized mu-opioid agonist, may offer advantages for neurosurgical procedures in which prolonged anesthetic effects can delay assessment of the patient. This study compared the effects of remifentanilnitrous oxide on cerebral blood flow (CBF) and carbon dioxide reactivity with those of fentanyl-nitrous oxide anesthesia during craniotomy. ⋯ Remifentanil and fentanyl have similar effects on absolute CBF, and cerebrovascular carbon dioxide reactivity is maintained.
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Randomized Controlled Trial Clinical Trial
Single-breath vital capacity rapid inhalation induction in children: 8% sevoflurane versus 5% halothane.
The authors compared the speed of induction of anesthesia with sevoflurane with and without nitrous oxide with the speed of halothane and nitrous oxide using a single-breath vital capacity induction. ⋯ Induction of anesthesia with a single breath of 8% sevoflurane with or without 66% nitrous oxide is more rapid than with 5% inspired halothane with 66% nitrous oxide in children. The incidence of movement and dysrhythmias during a single-breath induction with sevoflurane are less than they are with halothane.
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Pain resulting from a usually nonpainful stimulus (allodynia) is a common characteristic of neuropathic pain. Among animal models of allodynia, tight ligature of lumbar spinal nerves has been of special interest because it has been reported to be relieved by sympathectomy. The purpose of this study was to determine whether spinal analgesic agents, which have opposite effects on sympathetic nervous system activity (clonidine decreases it and neostigmine increases it), have differing efficacy in this model. ⋯ These results disagree with previous observations that mechanical allodynia in this animal model depends on sympathetic nervous system activity. Therefore, intrathecally administered analgesic agents, one that reduces sympathetic outflow from the spinal cord (clonidine) and one that increases it (neostigmine), were similarly effective in this model.
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Randomized Controlled Trial Clinical Trial
Intrathecal sufentanil dose response in nulliparous patients.
Intrathecal sufentanil provides effective analgesia during the first stage of labor. A range of doses has been reported to provide adequate pain relief. This study determined the dose of intrathecal sufentanil that produced acceptable pain relief in 50% of nulliparous patients (ED50) who requested labor analgesia. ⋯ This is the first study to determine the ED50 of intrathecal sufentanil in spontaneously laboring nulliparous patients. As dose-response curves are determined for other labor analgesics, future studies can compare equianalgesic doses or dose combinations.
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Airway pressure-release ventilation provides ventilation comparable to controlled mechanical ventilation (CMV), but with lower peak airway pressures and less dead-space ventilation. To obtain these advantages for patients administered general anesthesia, the authors (1) designed a mode similar to airway pressure-release ventilation, intermittent continuous positive airway pressure (CPAPI), and compared its efficiency with that of CMV; and (2) assessed the accuracy of end-tidal carbon dioxide tension (PETCO2) as a monitor of the partial pressure of carbon dioxide in arterial blood (PaCO2) during CPAPI compared with during CMV. ⋯ During CPAPI, less ventilation was necessary to produce a PaCO2 comparable to that during CMV. This represents a significant reduction in dead-space ventilation, improved efficiency of ventilation, and a lower value for P(a-ET)CO2. Compared with CMV, CPAPI also improves the accuracy of PETCO2 as a monitor of PaCO2.